I've done this a number of times as well. Sometimes intentionally, sometimes it just sort of happens by coincidence. I can tell you that I have Street Fighter Alpha/Zero 3 on every console & handheld it was ever released for because it's my favorite game of all time. (Yeah, I said it) I also have multiple copies of various other Street Fighter games, Metal Slug games, various fighting games, and some other random things. Prior to the current generation, there were usually enough differences in the console ports that made some games worth checking out on more than one system, but as already discussed here, the current generation of consoles offers little differences aside from the occasional exclusive character.